Several neuropsychiatric syndromes including Altzheimer's dementia, Gilles de la Tourette's syndrome are being studied in terms of memory function, neuroendocrine function, and possible pharmacological treatment. The pathophysiology and neuropharmacology of anorexia nervosa and orthostatic hypotension is also under investigation. Clinical trials are underway with several cholinergic agents (lecithin, THA, arecholine) with regard to memory function in Altzheimer's dementia. A clinical trial of lecithin in Gilles de la Tourette's syndrome was not efficacious. The blood pressure responses to infusions of norepinephrine, angiotensin, and tyramine has shown that idiopathic orthostatic hypotension patients have alpha adrenoreceptor supersensitivity while those patients with multiple system atrophy, in addition, lack baroreceptor modulation of the pressor response. Insulin tolerance studies have revealed that the autonomic defects in patients with chronic autonomic failure may include vagal dysfunction and deficient adrenal medullary responses to hypoglycemia, however, other counter-regulatory hormones (glucagon, growth hormone, cortisol) are secreted appropriately despite the absence of a catecholamine response. Cerebrospinal fluid studies in anorexia nervosa have demonstrated decreased serotonin and dopamine turnover during the acute illness.